luckadjusted

Week 15 2022 · December 15, 2022

49ers at Seahawks, Week 15 2022: who deserved to win?

The 49ers beat the Seahawks 21–13, and it was no fluke: replayed with the way both teams actually played, the 49ers win 9 of 10. The Seahawks had the bounces: injuries alone were worth 7.4 points to the Seahawks.

Before kickoff the 49ers were 59% favorites. The biggest swing (Q3, 12:52 left): Roughing the Passer on the 49ers (Nick Bosa), 15 yards, wiping out the play, worth 10 points of win probability to the Seahawks.

Final

San Francisco 49ers 21
Seattle Seahawks 13

December 15, 2022 · Lumen Field · Closing line: 49ers −3

Luck index +11 49ers about even · −11 Seahawks

Each team’s own plays from this game, resampled into new drives 4,000 times: with the way both teams actually played, how often does this performance win? How the replay works

Ten replays. 49ers win 9, Seahawks win 1.

  1. 1 SF 41 SEA 9
  2. 2 SF 33 SEA 9
  3. 3 SF 33 SEA 13
  4. 4 SF 30 SEA 14
  5. 5 SF 13 SEA 0
  6. 6 SF 34 SEA 23
  7. 7 SF 35 SEA 28
  8. 8 SF 32 SEA 28
  9. 9 SF 19 SEA 17
  10. 10 SF 19 SEA 26

Three other ways to ask

Each answers a different question, so none of them replaces the replay above.

The closing betting line, turned into a probability. What everyone knew before the game.

The line plus what this game showed, weighted by how much one game can tell. It stays close to the line because one game says little.

Every kick, fumble bounce, drop, conversion and judgment call redrawn; everything else fixed. The narrowest view of luck.

How 4,000 replays ended

49ers win 89% of them, Seahawks 11%, counting the 2% still level after regulation as half each. The line is what actually happened: 49ers by 8.

Show as a table
Final margin in the replaysShare of replays
49ers by 17+50.6%
49ers by 9–1621.3%
49ers by 1–816.8%
Level after regulation1.7%
Seahawks by 1–86.3%
Seahawks by 9–162.3%
Seahawks by 17+0.9%

Where the luck was

Take the luck out

The final margin was 49ers by 8. Remove the luck, one kind at a time, and it becomes 49ers by 22.3.

Each row takes one kind of luck out of the margin. Color shows which team it helped. Luck shares are the fitted ones (how much of each component is luck).

The kicks

How likely each kicker was to make that kick (his own record, the distance and the weather), and what happened.

  • J. Myers, 38 yds made · 90% expected
  • J. Myers, 51 yds made · 71% expected
  • R. Gould, 43 yds missed · 82% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

When it happened

Seahawks’ chance of winning

As low as 0% and as high as 58%. Numbers mark the biggest luck moments, listed below.

nflfastR’s in-game win probability. It ignores the betting line, so it starts near even. Shaded above the middle while the Seahawks were ahead in it, below while the 49ers were.
#WhenWhat happenedWin probability forNext drive
1 Q1 6:37 The 49ers converted 3rd & 33rd & 4th downs · 54% expected +6% SF SF: Touchdown
2 Q2 14:09 The Seahawks were stopped on 3rd & 53rd & 4th downs · 39% expectedTaunting on the Seahawks (D.K. Metcalf), 15 yardsJudgment calls · 13 flags in 3562 snaps before, position avg 1 per 412 +9% SF SEA: Punt
3 Q2 7:34 The Seahawks converted 3rd & 133rd & 4th downs · 22% expected +5% SEA SEA: Field goal
4 Q2 5:01 The Seahawks got away with an interception-worthy throwInterceptions · 46% expected to stay out of the defense's hands +6% SEA SEA: Field goal
5 Q2 1:08 The Seahawks fumbled and the 49ers recoveredFumble bounces · loose balls are close to 50/50 +8% SF SEA: Punt
6 Q2 0:41 Offensive Pass Interference on the Seahawks (D.K. Metcalf), 10 yards, wiping out the playJudgment calls · 13 flags in 3562 snaps before, position avg 1 per 412 +8% SF SF: End of half
7 Q3 12:52 Roughing the Passer on the 49ers (Nick Bosa), 15 yards, wiping out the playJudgment calls · 7 flags in 2560 snaps before, position avg 1 per 277 +10% SEA SEA: Field goal
8 Q3 10:38 Offensive Holding on the Seahawks, 11 yards, wiping out the playJudgment calls +6% SF SF: Punt

Missing players

Key players (usually on the field for half the snaps or more) who missed this game or part of it, valued by position and quality. The same players are missing in every replay, so this counts as luck in points only.

  • Jimmy Garoppolo (SF QB), out, replaced by b.purdy · 6.3 pts
  • Deebo Samuel (SF WR), out · 1.1 pts

Adjust the assumptions

Disagree with how much of a fumble bounce or a pass interference call is luck? Change it and the coin-flip replay reruns in your browser.

Only coin-flips re-rolled

49ers 94% · Seahawks 6%

Final margin
49ers by 8
Luck in points
14.3 for the Seahawks
Luck-adjusted margin
49ers by 22.3
Replay with same day's form
49ers 89% · Seahawks 11% unchanged: why
How much of each is luck?

0% treats it as skill, 100% as pure luck. The tick is our fit.

What counts

We tested momentum on 19,000 lucky breaks and found none, so it's off by default. Why

Flip a play

Force the other outcome, in this game and in every replay: a made kick becomes a miss, a stop becomes a conversion, a flag goes the other way.

About these numbers

Play-by-play and win probability from nflfastR via nflverse; kicks valued against each kicker’s own record; drops and interception-worthy throws from FTN charting; injuries from snap counts and injury reports.

Methodology and validation · All Week 15 2022 games · 49ers · Seahawks

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